The prior art of paper moving systems for plotters is best exemplified by U.S. Pat. No. 4,834,298 dated May 17, 1983 to LaBarre, et al and assigned to the assignee of the present invention. In the LaBarre arrangement, paper or other printing media supported on a plotting table is moved by opposed drive and idler rollers positioned at either lateral side of the paper to pinch the paper edges therebetween. The paper moving rollers are preferably provided with a roughened surface which engages the paper by making slight indentations therein to minimize slippage. In one embodiment, yaw and side to side movement of the paper is minimized by ramps which bend the paper edges upward from the plane of printing and mounting of the idler rollers on pivotable axles such that the idler rollers urge the paper edge toward a paper edge stop.
Other prior art paper drives employ spring urged toothed drive rollers which mesh with perforations in the edges of the paper or other print media to pull the media through the print zone.
While such systems are acceptable, a paper moving system is desired which will provide edge to edge tension in unsupported and unperforated paper across the print zone without bending the paper edges or permitting yaw or side to side paper movement. In such an arrangement, a paper table or platen roller to support the paper or other print media in the printing zone is optional and the arrangement is therefore capable of opening up the print zone to make room to accommodate other apparatus such as means for pre or post-print heating of the print media. Generally speaking, the smaller the printer, the less necessary is a platen roller or paper table whereas in printers capable of handling larger media, a platen roller or paper table can be used if desired with the paper moving system disclosed herein.